The projector-type display apparatus or the projector is, for example, connected to an image generation apparatus, such as a personal computer, via a video cable and is used for presentations and other purposes. Analog RGB signals generated by the personal computer are input into the projector via the video cable and are projected as images on a screen or the like.
Under such working conditions, the personal computer simply exerts the function of outputting video signals to the projector. The work of connecting the personal computer with the projector via the video cable on every occasion of use is rather troublesome and time-consuming.
It is accordingly convenient to store data for the presentation in the projector. Under the recent development of the network environment, it is further convenient to distribute display video data to the projector via the network. In the structure of storing the presentation data in the projector, some protection policy is desired to prevent the stored data from being displayed by any third entity.
The projector for projecting and displaying images is capable of large screen display and is thus widely used in lectures, meetings, and school lessons. The projector is generally combined with a computer, which functions as an image supply apparatus to the projector and also as a control apparatus for controlling the working state of the projector, to constitute a display system. The computer as the control apparatus is conventionally connected with the projector via an interface like RS-232C and carries out various control operations to control the projector.
The user's control of the working state of the projector is implemented by execution of a specific software program by the computer. Otherwise the working state of the projector may be controlled with a remote control attached to the projector.
When there is a requirement to change the working state of the projector in the middle of a meeting, for example, an operator who operates the control apparatus generally carries out the change. When one of multiple participants, for example, in the meeting desires to change the working state of the projector, the participant should request the operator to change the working state of the projector.
In the case of changing the working state of the projector according to this procedure, there is a possibility that the request of change is not smoothly transferred from the participant to the operator. If the participant desires to directly operate the control apparatus, the participant should move to the position where the control apparatus is located. Because of these factors, the display system utilizing the prior art projector has poor operability.
The user operates a remote control RM and causes a projector PJZ to carry out diverse processing as shown in FIG. 30. The projector PJZ projects and displays an image on a screen SC, in response to an analog video signal AV1 supplied from an image supply apparatus 1900. The user operates, for example, the remote control RM to superimpose an ornamental image like a pointer image PPJ on an original image ORG projected and displayed on the screen SC. Such superimposition of the ornamental image on the original image ORG enhances the effects of the presentation.
There are, however, difficulties in causing the projector PJZ to execute the processing with regard to the contents of the projected and displayed image through the operation of the remote control RM. This is ascribed to the rather poor operability of the remote control RM. In the case of sequential presentations by a plurality of people with one projector, it is required to successively transfer the remote control RM among the respective presenters. This prevents smooth progress of the sequential presentations.